It would be nearly impossible to continue, due to the final mission in the anime. Let's just assume that immediately after the final scene, Kurono goes back to the room. What do you think the odds are that he would trust Gantz? This would screw up the whole "Let's get 100 points so we can revive people" arc because Kurono would assume Gantz was just tricking him. Also, I think Kurono would probably give up on life.

The only solution I can see would be to have those last few episodes be a dream...but that would piss people off.

After the Buddha mission, it branches off. The final mission is rather strange: The new Gantzers are told to kill Kurono, who is identified as "Kurono Alien". Naturally, they all die either at the hands of Kurono or eachother. Kurono is left the only survivor. Gantz then brings him back to the train station where he runs from the train once again. He turns around as the train is about to hit him, makes a gun sign with his hand, and says "Bang" (Yes, it's a Bebop ripoff). The screen goes white, and you see Gantz's room...only Gantz has disappeared. The final shot after the credits is the empty train station as another train goes through.

There was no resolution at all, and they made Gantz less sci-fi and more mystical, as all the Final Mission characters appeared earlier in the series off to the side and that creepy old lady who appears to Kurno whenver there was a mission about to happen.

The end of Gantz anime kinda reminded me of Final Destination, as Kurno HAD TO DIE! acording to Gantz, and everyone died at the end.

Also ath the begining of the series Gantz showed up inside the room, whcih is odd as well.